As the wizard hobbled and pranced sideways out of the way, the Weasley party moved forward a few steps and Harry read the floor guide: ARTEFACT ACCIDENTS… Ground floor Cauldron explosion, wand backfiring, broom crashes, etc.

Harry leapt to his feet and, making sure he had his bag and that the Invisibility Cloak was completely covering him, he wrenched open the door and hurried out of the office after Filch, who was hobbling along faster than Harry had ever seen him go.